Dell Inspiron 1545 wont connect to my wireless network?

I just purchased a new Dell Inspiron 1545 and had my dad set everything up for me at his place. He installed Norton Anti Virus protection as well as Windows Professional. He was able to connect to the internet at his house, but when I brought the laptop back to my apartment and tried to connect to my internet, a box popped up in the bottom corner and said "Windows was unable to connect to this network". It doesn't even ask me for a password, whereas other random networks I checked for fun did. I also have an iMac where I am able to operate the connection from. Am I doing something wrong? Is there a setting that I have to keep my connection on? Please help.